With the development of communications technologies, most terminal devices such as mobile phones require multi-frequency coexistence. For example, introduction of a Long Term Evolution (LTE) frequency range requires increasingly large bandwidth of an antenna, and a common antenna cannot meet a requirement for antenna bandwidth in limited space. Therefore, a switch needs to be used to control the antenna to switch to different resonance frequencies, so as to increase bandwidth of the antenna.
However, a current switch is disposed in the middle of an antenna circuit, which generates switch loss, causing reduced antenna efficiency; however, using a common antenna without a switch so as not to reduce the antenna efficiency increases space occupied by the antenna.